Various perfume compositions are available to mask, deodorize, and/or remove malodors in the air. These compositions may be dispensed by air freshening systems, including electrical (i.e. energized) plug-in diffusers, passive (i.e. non-energized) diffusers, trigger spray dispensers, and aerosol spray dispensers. In many instances, adequate delivery of perfume compositions into the air requires the use of evaporation or dispensing aids.
Passive or diffusive air fresheners, for example, may utilize liquid compositions containing 20% or more volatile organic compounds (“VOCs”) as a perfume evaporation aid. “VOCs” as used herein means volatile organic compounds that have a vapor pressure of greater than 0.2 mm Hg measured at 20° C. and aid in perfume evaporation. Exemplary VOCs include the following organic solvents: dipropylene glycol methyl ether (“DPM”), 3-methoxy-3-methyl-1-butanol (“MMB”), volatile silicone oil, and dipropylene glycol esters of methyl, ethyl, propyl, butyl, ethylene glycol methyl ether, ethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, or any VOC under the tradename of Dowanol™ glycol ether.
In passive and energized air diffusers, DPM and MMB are commonly used. In aerosol dispensers, a commonly used dispensing aid or propellant is hydrocarbon, which is a VOC. VOCs may be undesirably in some product applications given its solventy smell. Additionally, some VOCs are currently regulated by the Environmental Protection Agency and California Air Resource Board (“CARB”). VOCs, classified by CARB regulations, can be found in Article 2, §94508(a)(144) of the California Consumer Products Regulation. In view of the aforementioned concerns and the desire to protect the environment, approaches for reducing VOC content are desirable.
One approach for reducing the VOC content is to simply lower the amount of VOCs in the formulation. However, lowering the VOC content can adversely affect performance. For example, in passive and energized air diffusers, VOCs may aid in keeping perfume components in solution which aids in evaporation profiles of the solution as it diffuses from the diffuser. As such, reducing the VOC level may compromise the delivery of an intended perfume character. In the case of aerosol spray dispensers, reducing the propellant content may leave product in the dispenser even after the propellant has been depleted. It may also increase the particle size of the dispensed product, which can lead to excessive surface deposition. Another approach for reducing VOC content in aerosol spray dispensers is outlined in U.S. Pat. No. 7,014,127. This approach utilizes at most 25% of a liquefied gas propellant, free of butane, in combination with a specific range of can pressures and valve orifice dimensions.
As such, there continues to be a need for improved compositions, including air freshening compositions, having components that provide continuous fragrance yet are substantially free of VOCs.